1/10th of customers are likely (gross-margin) unprofitable. That doesn’t mean you should “fire” them. But it’s a calculation worth understanding, and a phenomenon worth measuring. And sometimes, changing your policy or product to reduce that set, is a quick and strategic way to generate profit.

1/10th of customers generate 10x more support calls than the rest. Some of that is OK, but some of that might be a signal about your product, or about your customers, or about those customers.

Still, it’s useful to assume there is a 10x truth, and spend your time seeking that truth, rather than worrying about and fiddling with one hundred variables, almost none of which will turn out to be important.